Underreamer.



C. T. MAPES.

UNDERREAMER.

APPLICATION FILED r5 17,1912

Patented Dec. 21, 1915.

Fl Ge..I

' so that the insertion and removaly vof the ommen T. Marias, or GRAFTON, rENNsYLvANIa l UNDEBREAMER.

Specification of Letters Patent.' Patented Dec. 21, 1915.

Application led February 17',I 1912. I Serial N o. 678,355.

To'aZZ whom t 'may concern.'

Be it known that I, CLARENCE T. MAPEs, a resident of Grafton, in thc county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Underfreamers, of which the following Ais a specification. A

This invention relates to an underreamer of the general type illustrated in Letters Patent No: 923,677, granted tome Junel, 1909, whereinthe -reamer :body is recessed upwardly, from its lower extremity to vreceive and confnethe slanks of a pair of op; posed. slips, the Shanks being movable vertically and' tiltable within the body cavity to permit the slips to expand into cutting position and to be contracted from such position." ln this type of undcrreamer vthe slipV shanks are so confined within the-body cavity as to. firmly brace; and hold them in position'` to resist the excessive strains to which the slips are subjected lwhen inaction.' 'It is necessary to keep the body recess clear of' drillings, dirt, etc., so that the slips may move with certainty and accuracy into and, 1

out of cutting position. 4 AAt the same time the Aconstruction .should besuch as lto ai'ord ready; entrance of the slip'ishanks into the holding and bracing socket or cavity. It is `alsode'sirable to avoid as far as possible the formation of irregularities in the. coperat ing surfaces Aor faces of the socket andthe slips, such surfaces being'diiiicult to form ,and tending to cramp and obstruct the slips, especially in the presence-of drillings,l and other foreign matter jthat may 'work into the slip confining cavity. ,Y

With the foregoing requirements in-view, one object of the present inventionis to provide for closingr the space between the opposed slips when thelatter are in'cutting position, the closing means being removable without offset depressionsor projections so also that there is no tendency for' the slips. to cramp, or to be obstructed by accumulations ofv sand, etc., whlch surface irregulari-v that said surfaces may be vreadily formed,

ties when present are liable to induce.

In the accompanying drawings, Figuregl is a vertical section of the underreamer with the parts set for cutting, and Fig.. 2 is a similar view with the parts contracted, as when' being lowered or raised in a well casing. Fig. 3 is a side elevation of the reamer with the slipseXpanded into cutting position. VvFig. 4 is a sectional elevation on line 4 4 of Fig. 3. Fig. 5 is a detail view of form illustrated -in my vabove mentioned patent, the upper portion thereof being circular in cross-'section at `5, and from this upper circular portion the cavity widens 7 to receive the slip shank extremities, as Will be lpresently described. The wider walls 4 of cavity 4 lare smooth, being .un.

such as are shown in my former patent, and

Vinthe present construction guide iianges on the slips`as illustrated' in said patent'are omitted, so that the faces ofthe slipsfand the cavity walls are smooth and there is no yopportunity for drillings or dirt to collect,y .norA tendencyon thepart onf the slipsto' cramp. Also, the omission of such irregular features simplifies and facilitatesA manufacturev of the parts, and this feature will be especially appreciated when it is remembered that the tool body and slipsare. usu- 2 ally formed of steel.

The pair of opposed slips 8 have their shank portions entered in body cavity 4, the adjacent faces of the slips being recessed at 10 to receive the The'ad end ll.of rod 11,wh ich latter extends upwardly through bore .12 of the body, with .spring 13 `con. lined thereon .as inmy said former patent.

The slip shanks 9 are of a form to readily enter. cavity 4 when `the latter Ais unob- 'structed, and are of such` shape as to move vertically therein and also tilt as is reouiredv 'one of the slips. Fig. 6 is an inverted end vview of the reamer body.l Fig.` 7 is a sec-v downwardly into substantially oval form, the .opposite narrower wallsG having oifsets- A interrupted" by depressions or g'uideways,l 'i

. for spreading the slips into cutting position and .forretr'acting them so that they may pass within the wall easing. The upper extremities 9 ofthe Shanksare shaped com- 'Shanks are 'of such form as to accurately fit the walls ,of cavity 4 when' the .slips are in the set position' shown in Fig.- 1, the rounded outeredgesjt "of the Shanks fitting the narrower curved 'walls 6' of cavity `sna'nd -the-Substantiallylflat side faces ofthe Shanks fitting' smoothly d u l against the uninterrupted Wi eriwa s41- lAbutments 14 atthe'junctureot the slip' body' and' shanks are ,disposed at angles coniplementary with the lower extremity 14 of b ody 2 si1` i'iounding cavity i.' In the adaptation of Figs. l andQ these abutting surfaces converge inwardly and'downwardly toward A the center of the tool, although they may converge inwardly `andf upwardl.y, 'as inl Fig. 8.

' Slip Shanks 9'are of.

may be readily entered 'within cavity il when the latter is'wholly unobstructed. It is desirable, however, to close the space between the Shanks when the slips' are in cutting positi0n,thereby preventing dirt from entering between the Shanks and lodging in cavity 4e. "To .accomplish this 'JI provide a removable bridging member which is put 'in place after the slips 'are1insertedand which is embraced vby them, said member closing the intervening space" when the slips are lset for cutting, and also holding the vslips against complete withdrawal from the body cavity. In the present. adaptation,

this bridging-member is circular' in -crosssection and may take the form of a' roller '-15 which is removably 'held by the trans-A verse pin 16, the pim extending through apertures in the, depending' abutment-forming portions 17 at opposite sides of the lower extremity .of body 2. jln.v addition to exc luding drillings, etc.,said. member com-v bines with labutments 17 in providing back# 'ing Surfaces clear across the reamer body.

for the slip faces 18. The adjacent' faces of Shanks 9 are oppositely recessed -at 1Q to I embrace when contracted the cross member '15, and with the latter' of curved 'form-re` Vcesses 19 may be formed by drilling', thereby avoiding tedious -andv expensive milling.

The transverse memberis not' vthe Way,v lthe slips closing compactly therearound' as in Fig. 2, and' at the same time said mem the' slip-'elevating movements,v

'creasing after 'such start has been A being. substantially minimum when the'slips Such size and shape that when embracing'the headed' rod 11 they .vated and to contractv -slip operating means.

to drop out'as would occur if rod 11 shouldV break or becomefdisengaged from the slips.

By the use of the circular or rounded bridging member with the complemental vber renders it quite impossible for the slips i configuration ofrece'sses 19, it will be seen that 'when the slips are in their lower posi-v tion, a maximum surface'contact is had between said member and the"slips. .This exf.

tended surface contact of member and slips is not materially afectedatY the'beginning of due to the operation of the inclined faces T on the upper .ends of the slips, so that at thje time.

when theelevating movement begins the stress 1 s somewhat Adistributed-v over these contacting surfaces, lthesurface contact de- 'are expanded orin' -their elevated. position.-

As will be obvious, this tends to decrease localiaation of wear on th'e.slips. -fFurther more, the makingof this device intheform tion to vbe" provided, butany tendency of nonew'or the other-slipsto Stick during the .movements of the slips would tend to shift yof av roller. not only enables a replacing acthe roller 'on its 'axisand' thus presenta new@ surface, thereby tending to decreasetlieet' f e'ct of wear. on the bridging member.

1 claim '1. The combination lof a reanier body hav l ing its lower end formedwith an upwardly `extending' laterally closed cavity substantiallyA oval in horizontal crosssection with cavity. flat and uninterrupted and .unindented from the bottoni to .the top of-the .cavity and with the opposite end walls of the cavity curved, a device removably bridg-` ing the lower end ofthe cavity atv the center flat side walls, apair of opposed' slips ,shouldered at' their outer sides between their ends to provide ledges for engaging the .lower extremity of the body 'when the Slips are conshouldersformed with 'uninterrupted and unindented flat side facescom'plementary with the flat side walls of the body recessr A io'o the opposite horizontall)1 longer wallsof the7` (thereof. and supported by the said oppositei traCted,l the' portions ofA the slipsabove 'the I and the' other outer surfaces' of said- Slip portions rounded complementary lwith the rounded walls ofthe recess, the opposed inner' faces ofthe slips having' recesses com- 'plemental to and adapted to embrace the said bridging device when .the slips are lowered and contracted, said device and the complemental recesses having configurations tending to provide a decreasing surface contact' therebetween Aduring velevating movements of the slips, thewall of the' body re- -cess and the slips shaped to cause the lower to expand when elewhenlowered, and

portions ofl the slips 2. The combination of a reamer body having its lower end formed with an upwardly extending laterally closed cavity substantially ovall in cross section, the body formed at opposite sides of the smaller diameter of the cavity with downward extensions which provide lateral abutments and with the portions of the body extremity between said extensions comprising vertical abutments, a pair of opposed slips shouldered between their ends to provide ledges which engage the vertical abutments formed by the body extremity, the adjacent faces of the slips formed with transverse surfaces which intersect the ledge-formed surfaces and which are adapted to engage the lateral abutments formed by the body projections whereby the slips are reinforced by the veitical and lateral abutments in substantially the same transverse plane, a device removably secured between the body projections and constituting continuations of the abutmentforming surfaces of the latter thereby providing an uninterrupted transverse abutmentl for each slip from side to side thereof, the portions of the slips above the said shoulders forming Shanks having flat sides and curved ends which fit the body recess, the adjacent faces of the shank portions recessed so that when lowered and contracted they embrace the removably inserted device with ithe latter preventing complete Withdrawal of the slip shanks from the body recess, -the wall of the body recess and the slip Shanks shaped to cause the depending portions of the slips to expand when elevated and to contract when lowered, the slip surface-contact with said device decreasing during the elevating movements of the slips, and slip operating means.-

3. The combination of a reamer body recessed upwardly upon its lower end with the recess closed laterally, a pair of opposed sllps having shank portions movable vertically and tiltable within the cavity for moving into and out of set position, the slip shanks being of a size t0 enter the body 'cavity when the latter is unobstructed and with the adjacent faces of the slip Shanks formed with opposite curved recesses, a roller removably mounted transversely within the bodv cavityl between the slips and adapted to be embraced by the opposite curved depressions in thev adjacent faces of the slip shanks, the surface contact of roller and slips decreasing during the elevating movements of the slips to provide a minimum contact when the slips are in elevated position, and slip operating means.

In testimony whereof I affix my signature in presence of two witnesses.

CLARENCE T. AMarias.

Witnesses J NEsBrr, F. E. GAITHER, 

